Transport roller for sheet material

ABSTRACT

Roller apparatus for transporting sheet material such as photographic film and the like between two adjacent rollers of the apparatus is disclosed. One roller of the apparatus disclosed is a rigid roller and the second is resilient. The second roller includes an elongated substantially rigid shaft and a resilient cylindrical outer member mounted on the shaft. The cylindrical outer member is 60 to 95 percent filled with small spheres which move inside of the resilient roller upon rotation of the resilient roller to maintain a uniform and also light pressure in the nip or pinch area of contact between the two rollers when the rollers are rotatably mounted adjacent each other in bearing mounts.

United States Patent Edward H. Savela lnventor Minneapolis, Minn. Appl. No. 884,644 Filed Dec. 12, 1969 Patented Nov. 23, 1971 Assignee Pako Corporation Minneapolis, Minn.

Continuation-impart of application Ser. No. 680,775, Noy, 6, 19127, nowgbandoned.

TRANSPORT ROLLER FOR SHEET MATERIAL 9 Claims, 4 Drawing Figs.

US. Cl 226/190,

1m. (:1 B65h 17 20,

Primary Examiner-Joseph Wegbreit Attorney-Wicks & Nemer ABSTRACT: Roller apparatus for transporting sheet material such as photographic film and the like between two adjacent rollers of the apparatus is disclosed. One roller of the apparatus disclosed is a rigid roller and the second is resilient. The second roller includes an elongated substantially rigid shaft and a resilient cylindrical outer member mounted on the shaft. The cylindrical outer member is 60 to 95 percent filled with small spheres which move inside of the resilient roller upon rotation of the resilient roller to maintain a uniform and also light pressure in the nip or pinch area of contact between the two rollers when the rollers are rotatably mounted adjacent each other in bearing mounts.

throughout the length of the roller 1 TRANSPORT ROLLER FOR SHEET MATERIAL CROSS REFERENCE BACKGROUND The invention relates to an improvement in rollers for transporting sheet material therebetween and more particularly to rollers for transporting thin material such as photographic film and the like.

Presently, known arrangements of pairs of rollers for transporting film include those arrangements where each roller has a relatively rigid or firm cylindrical body of plastic, hard rubber and the like mounted on a shaft. Roller arrangements having such a construction require that the ends of the shafts be mounted in resilient mounts in order to maintain light and uniform contact throughout the length of the roller. Without resilient mounts at the ends of the shafts, the shafts bow and uniform driving contact is not at all maintained throughout the length of the rollers. Even with the use of resilient bearing mounts, however, the problem of providing uniform and also light contact along the entire nip or pinch area between the two rollers, which may be relatively long, is notsolved.

Additional roller arrangements known use a resilient roller such as a roller constructed from an outer layer of rubber, foam, or other resilient material or from a thin resilient material which acts as container for a fluid filling the roller. The problem of maintaining a uniform and also light contact in the nip or pinch area is not totally alleviated by using this type of resilient rollersince an increase in pressure inthe nip or pinch area is immediately transmitted by the fluid to the remainder of the roller and thus relieved in the nip or pinch area. Also, when resilient foam rollers are left idle for a period of time, they tend to develop a flat area in the nip area in contact.

Present known rollers include a shot filled completely'flexible roller as disclosed in US; Pat. No. 3,438,100. However, this device is only suitable for use as the upper'roller in a pair of rollers transporting a horizontal web as it depends on the weight of the shot to provide the nip pressure. The present invention is, however, satisfactory for a pair of rollers transporting a sheet material vertically and also horizontally, with no dependence sn the weightofthefiller.

SUMMARY The present invention solves the above and other problems of prior art roller arrangements for transporting sheet material by providing a roller arrangement including a pair of cylindrical rollers rotationally mounted within bearings adjacent one another such that portions of their surfaces are in contact in a nip or pinch area. In the preferred embodiment, one roller is a rigid roller while the second is a resilient roller. The resilient roller includes a resilient hollow cylinder mounted about a shaft and sealed about its ends with respect to the shaft to create a void about the shaft and within the resilient roller. Also in the preferred embodiment, small, glass spheres are placed within the void of the resilient roller such that approximately 80 percent of the volume of that void is filled with the spheres. The rollers are arranged such that rotation of the rollers brings the spheres into compression adjacent the nip area to maintain a light and also uniform pressure along the nip area, and frictional engagement between the multitude of spheres within the one roller prevents an immediate relief of the compressional forcesin this area.

The uniformity of the light pressure along the nip is relatively unrelated to the difl'erences in thickness of the sheet material to be transported to the extent that sheet material of different thicknesses can be transported between the rollers of the roller arrangement of the present invention side by side without distorting the uniformity of pressure upon either material.

It is thus an object of the present invention to provide an improved transport roller arrangement where one roller has a resilient body whereby light and also unifonn contact with a companion roller may be maintained throughout the length of the rollers.

It is an additional object to provide a transport roller arrangement of the aforesaid type with which sheetmaterial of different thicknesses can be transported at spaced points between the rollers with light and also uniform roller contact maintained on the different'material.

DESCRIPTION OF THE DRAWINGS These and other more detailed and specific objects will be disclosed in the course of the following specification, reference being had to the accompanying drawing, in which:

FIG. 1 is a top plan view of a pair of rollers embodying the invention, portions thereof being broken away, other portions being shown in section.

FIG. 2 is an enlarged longitudinal section of one roller on the line 22 of FIG. 1.

FIG. 3 is a sectional view on the line 3-3 of FIG. I.

FIG. 4 is a perspective view of one of the tubular supports for one roller removed from the roller.

DESCRIPTION Referring to the drawing in detail, the resilient roller A includes a shaft 10, the outer ends of which are rotatably mounted in bearings 12 and 14 and which are in turn mounted on supports 16 and 18, respectively. The shaft 10 has mounted on one end thereof the gear 20 which gear is driven by the driving gear 22, the driving means therefor not being shown, and in turn drives the identical gear 21 for purposes explained hereinafter.

Further provided are the identical annular support members 24 and 26 which are mounted on the ends of the shaft 10. Each support member includes a cylindrical base portion 28 from which extends frustoconical portion 30. The outer portion of the conical portion 30 tenninates in the annular shoulder 32. The entire support 24 is constructed from a resilient plastic, rubber or the like. The frustoconical portion 30 allows deflection and resiliency of the annular shoulder 32 formed on the outer end thereof. The base portion 28 of the support 24 may be secured to the shaft 10 by adhesive, a friction fit, or any known connection means.

The numeral 34 designates a cylindrical or tubular member constructed of a resilient plastic material which is mounted on the end support members 24 and 26 by providing an adhesive or heat seal between the outer surface of the annular shoulder 32 and the inner surface of the tubular member 34. The end support members 24 and 26 thus close the ends of the tubular member 34 to define a void 35 within the hollow tubular member 34.

Further provided is the filler material '36 for the tubular member 34 which is poured into the void 35.within member 34 before the end support members 24 and 26 are secured to the member 34 thereby sealing it off and maintaining the filler material 36 within the void 35 of tubular member 34. The filler material 36 is composed of a multitude of spheres, small by comparison to the diameter of member 34 and is poured into the void 35 within member 34 to fill the same approximately percent full, in the preferred embodiment. The void 35 within member 34 may be filled from 60 percent to percent with the filler material 36 depending upon the degree of compression of member 34 upon the shaft that is desired. In addition, the size of the filler particles 36 may vary considerably. Conventionally available glass beads of a 14 gauge size have been found as satisfactory with a resilient member 34 having approximately a 1 inch diameter and with a shaft 10 of approximately one-quarter inch diameter for compressive forces in the nip area of approximately 1 ounce per linear inch. The filler 36 provides a continuous resilient yieldable support for the resilient body 34 throughout its length, the filler yieldable with the resilient body 34 and having a measure of fluidity within the body 34.

Further, the diameter of the shaft 10 may be varied according to the roller length it must support. If the shaft diameter is increased for a given size filler 36 and body 34, there will be less resiliency to the body 34 of the roller. If the diameter of shaft 10 is decreased, the resiliency of the body 34 will be increased for there is more filler material 36 for fiow out of the nip area and into the void space left in the roller thus providing a relieving type of action. Also, when a long and slender pair of rollers must be used because of space limitations the maintenance of light and yet uniform pressure in the nip area between the rollers is very difficult but the present invention solves this problem.

A rigid cylindrical roller B is shown which is used as a companion roller to A for the transporting of sheet material such as S therebetween. The companion roller B has a solid cylindrical body 40 rather than the resilient cylindrical construction of roller A as shown, and body 40 of roller B is conventionally mounted upon a shaft 42 in a regular fashion. It may now be seen that gear 21 is mounted on shaft 42 to thus provide a rotational drive for roller B from drive gear 22 through gear 20 mounted on shaft 10. The ends of the shaft 42 are rotatably mounted in additional bearings 44 and 46 which are in turn again mounted on the supports 16 and 18, respectively. The longitudinal axes of rollers A and B are maintained by bearings l2, I4, 44, and 46 such that rollers A and B have a line of contact substantially parallel to the longitudinal axes of shafts l and 42. This line of contact is termed the nip or pinch area. As best seen in FIG. 3, because of the interrelationship of gears 20, 21, and 22, rollers A and B rotate in opposite directions about their common axes to thereby transport a sheet material S therebetween. As is conventional in the photographic arts, sheet material S may be in separate pieces or issue from a roll.

A threaded adjustment device 48 extends between bearing 12 supporting one end of shaft of roller A and bearing 44 supporting one end of shaft 42 of roller B. Adjustment device 48 allows the control of the distance between the bearings 12 and 44 in order to provide a further adjustment on the pressure between rollers A and B. A similar adjustment device 50 is connected between bearings 14 and 46 for a similar pur- The rollers A and B are arranged such that the longitudinal common axes of their shafts 10 and 42 respectively, are parallel to each other and to the line of contact between the rollers. Also, the shafts l0 and 42 in the preferred embodiment are spaced apart less than the distance required for the radius of solid roller B and the radius of resilient roller A such that solid roller B slightly compresses resilient roller A in the nip area between them, as is shown in FIG. 3. The preferred embodiment thus provides for more than contact between the rollers A and B, it provides compressive contact in the nip area along the line of contact between the rollers.

OPERATION With reference to FIG. 3 showing a cross-sectional view of the nip or pinch area of contact between roller A and roller B, as sheeting material S is passed between the oppositely rotating rollers, it follows the outer circular contour of roller B which provides a slight compression to the mounted hollow resilient member 34 in the nip area as explained. The compression of member 34 in the nip area causes a constant flow of glass spheres out of the nip area and into the void such as to provide a light uniform compressive force in the nip area. It is to be noticed that the compressive force is not immediately dispersed to portions of roller A removed from the nip area by the transmission of the compressive force through the filler media 36, as would be true if the filler media were a fluid or a compressive-type material such as foam rubber. Due to the frictional forces between the individual glass spheres, used in the preferred embodiment, the compressive force is maintained locally in the nip area and only slightly relieved until the roller A rotates and places a different sector of glass spheres under the compressive force. The partial filling of the void 35 within roller A allows this effect by allowing a slight flow of the spheres in the nip area into the unfilled area to thereby avoid a too rapid transmission and dispersal of compressive force in the nip area.

In practice, it has been found that contact force between the rollers must be sufficient to provide for transport of photographic film and yet be light enough to avoid damaging the film surface. Using the above-described construction for rollers of a 1 inch outer diameter, transport parameters between film located at different points along the roller varied by only 20 percent of the average reading when roller B was percent filled with 14 gauge glass beads.

CONCLUSION Thus, an improved roller arrangement has been presented which allows a light but uniform contact pressure along the entire line of the nip between the two rollers in spite of any bowing by the shafts supporting the rollers and in spite of varying thicknesses of sheet material passed between the rollers. Uniformity of the contact pressure has been found to be so good that the roller arrangement can function as a squeegee roller for removing excess moisture from a sheeting material emerging from a chemical bath. In fact, the transport arrangement of the present invention has application as a squeegee transport.

Now that the basic teachings of the present invention have been explained, many extensions and variations will be obvious to one having ordinary skill in the art. For example, the void 35 within roller A has been explained as preferably filled to 80 percent of its volume. As indicated, a filling within the range of 60 to percent will perform as explained and no limitation to a precise filling value is intended so long as the teachings of the present invention are followed. Also, no limitation to the precise lengths, diameters, sizes, or precise configurations is intended so long as the teachings of the present invention are followed. It will be realized by those skilled in the art that variations are necessary to accommodate the precise sheet thickness, sheet width, sheet weight desired in relation to a particular application.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims. Having now fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. Transport roller apparatus for sheet material, comprising in combination:

a. a first cylindrical roller including first and second ends;

b. first bearing means for rotatably mounting the first and second ends of the first roller;

c. a second roller, comprising:

aa. a shaft having first and second ends;

bb. a resilient hollow member having tubular sides of circular cross section and closed ends to define a void within the resistent hollow member, the member mounted around the shaft;

d. a multiplicity of spheres having radii which are small by I comparison to the radius of the resilient hollow member, the multiplicity of spheres being arranged within the void of the resilient hollow member to fill from 60 to 95 percent of the volume of that void and thereby allow movement of the spheres with the resilient hollow member; and

e. second bearing means for rotatably mounting the first and second ends of the shaft of the second roller such that the longitudinal axes of the shaft and the first roller are parallel and such that the first roller and the resilient hollow member of the second roller have a line of contact which line is substantially parallel to the longitudinal axes of the shaft and the first tubular roller, localized, partially unrelieved compressive forces on the spheres along the line of contact due to sphere frictional engagement in the partially filled void of the resilient member allowing the rollers to maintain uniform and light contact along the line of contact.

2. The transport apparatus of claim 1, wherein the axes of the shafts of the first and second rollers are spaced apart less than the distance required for the radius of the first roller and the radius of the second roller to thus provide the compressive contact between the rollers along the line of contact between the rollers.

3. The transport roller apparatus of claim 2, wherein the first cylindrical roller is a rigid roller.

4. The transport roller apparatus of claim 3, wherein the multiplicity of spheres comprises glass spheres.

5. The transport roller apparatus of claim 4, wherein the glass spheres fill approximately 80 percent of the volume of the void within the hollow resilient member.

6. The transport roller apparatus of claim 3, wherein the ends closing the resilient hollow member comprises:

aa. annular yieldable shoulder means connected to the 9. The transport roller of claim 8, wherein the spheres fill approximately percent of the volume of the void within the hollow resilient member. 

1. Transport roller apparatus for sheet material, comprising in combination: a. a first cylindrical roller including first and second ends; b. first bearing means for rotatably mounting the first and second ends of the first roller; c. a second roller, comprising: aa. a shaft having first and second ends; bb. a resilient hollow member having tubular sides of circular cross section and closed ends to define a void within the resistent hollow member, the member mounted around the shaft; d. a multiplicity of spheres having radii which are small by comparison to the radius of the resilient hollow member, the multiplicity of spheres being arranged within the void of the resilient hollow member to fill from 60 to 95 percent of the volume of that void and thereby allow movement of the spheres with the resilient hollow member; and e. second bearing means for rotatably mounting the first and second ends of the shaft of the second roller such that the longitudinal axes of the shaft and the first roller are parallel and such that the first roller and the resilient hollow member of the second roller have a line of contact which line is substantially parallel to the longitudinal axes of the shaft and the first tubular roller, localized, partially unrelieved compressive forces on the spheres along the line of contact due to sphere frictional engagement in the partially filled void of the resilient member allowing the rollers to maintain uniform and light contact along the line of contact.
 2. The transport apparatus of claim 1, wherein the axes of the shafts of the first and second rollers are spaced apart less than the distance required for the radius of the first roller and the radius of the second roller to thus provide the compressive contact between the rollers along the line of contact between the rollers.
 3. The transport roller apparatus of claim 2, wherein the first cylindrical roller is a rigid roller.
 4. The transport roller apparatus of claim 3, wherein the multiplicity of spheres comprises glass spheres.
 5. The transport roller apparatus of claim 4, wherein the glass spheres fill approximately 80 percent of the volume of the void within the hollow resilient member.
 6. The transport roller apparatus of claim 3, wherein the ends closing the resilient hollow member comprises: aa. annular yieldable shoulder means connected to the resilient hollow member; and bb. frustoconical portions connecting the annular shoulder means with the shaft of the second roller.
 7. The transport roller apparatus of claim 1, wherein the ends closing the resilient hollow member comprise: aa. annular yieldable shoulder means connected to the resilient hollow member; and bb. frustoconical portions connecting the annular shoulder means with the shaft of the second roller.
 8. The transport roller of claim 1, wherein the first cylindrical roller is a rigid roller.
 9. The transport roller of claim 8, wherein the spheres fill approximately 80 percent of the volume of the void within the hollow resilient member. 